Thermostatically controlled air



- Jan. '26, J. c. BARNES 'rasnuosnncuu CONTROLLED AIR mm FOR STOYES .Filod m. 19, 1941- attorney,

Patented Jan. 26, 1943 UNITED STATES PATENT OFFICE THERMOSTATiCALLY CONTROLLED AIR INLET FOR. STOVES Julius C. Barnes, Columbus, 6a., assignor to Columbus Iron Works 00., Columbus, 6a., a corporation of Georgia 7 Claims.

The present invention relates to improvements in thermostatically controlled air inlets, particularly for stoves of the type disclosed in the Dimmock Patent No. 599,225, dated February 15, 1898.

In the prior stoves of this type which are equipped with thermostatically controlled air inlets or dampers, the thermostatic element was either positioned closely adjacent the stove to be actuated by the heat of the stove only or was positioned remote from the stove to be actuated by the surrounding temperature exteriorly of the stove. In either case, these prior arrangements were not entirely satisfactory. In the case where the thermostatic element was influenced by the heat of the stove only, an inconsistent temperature prevailed in the vicinity of the stove.

This was due to the fact that the heat in the stove, even when very low, was suiiicient to affect the thermostat and keep the damper closed until the stove cooled considerably. Because the thermostatic element was thus positioned, the tem perature exteriorly of the stove did not have effective access to the thermostatic element whereby cooling of the same would open the damper and increase the intensity of the fire before the fire had subsided to the very low degree required to open the damper.

In. the case where the thermostatic element was positioned to be actuated by the temperature exteriorly of the stove only, it was found that the consumption of fuel increased enormously. It is a well-known fact that stoves of this character are usually located in enclosures where the insulation is not of the best and in such cases the thermostatic element would, to a large degree, be influenced by the temperature existing outside of the enclosure. Thus, such outside temperature would keep the thermostatic element cool a great deal of the time which in turn kept the damper open a great deal of the time with a continuous intensified fire in the stove. Under these circumstances; fuel would have to be fed into the stove almost continuously with the result that the cost of operating such stoves was increased.

It has also been found that where the thermostatic element is continuously subjected to intense heat it de-temperizes or loses its springing characteristics.

An important object of the present invention is to obviate the above-mentioned difllculties by providing a thermostatically controlled air inlet device which may be applied to conventionalheating stoves without materially altering the construction of the same and which will serve to automatically regulate the supply of air for combustion purposes and be responsive to the temperature of the stove as well as to the temperature surrounding the stove.

Another object of the present invention is to so arrange the thermostatic element that it will be cooled by the air exteriorly of the stove.

A still further object is to provide a thermostatically controlled air inlet which will at all times permit a certain amount of oxygen to be fed to the combustion chamber of the stove when the damper is fully closed.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawing, wherein like symbols refer to like or corresponding parts throughout the several views:

Figure 1 is a side elevational view of the device attached to a stove, a fragmentary portion of the stove being shown.

Figure 2 is a horizontal sectional view taken along the line 2-2 in Figure 1.

Figure 3 is a vertical sectional view taken along the line 3-3 of Figure 2.

Figure 4 is a fragmentary sectional view taken along the line 4-4 of Figure 3.

Figure 5 is a sectional view taken along the line 55 of Figure 3 and V Figure 6 is a front elevational view of the 1940, Patent No. 2,265,587, December 9, 1941, in

the name of Elliott S. Waddell.

Carried by the elbow I0 is the usual down draft tube 12 which in its upper end carries the usual rotatable closure l3. The operation of the construction thus far described is believed well .known in the art but it is understood that the cap 13 is provided with an opening which when placed in registry with the top of the down draft tube I2 permits oxygen to be drawn into the coinbustion chamber of the stove.

In accordance with the present invention the inner wall ll of the draft tube I2 is provided with an opening and the adjacent wall I! of the stove is provided with a similar opening. Both of these openings are of the same diameter and are coincident with each other and preferably are located near the upper portion of the tube and stove. The opening in the stove wall snugly receives the cup-shaped housing l6 which is provided with a beading I! to abut against the wall of the stove and serving as a seal for the opening and limiting the inward movement of the housing within the stove. The housing i6 is open at its inner end while its outer end Wall i8 is provided with a series, preferably three, of perforations l9 discharging into the stove body.

Within the draft tube I2 and abutting the opening therein is placed a cap member. 20 which is provided with an arcuate slot 2| and an opening 22. The diameter of the cap 20 is such that when it confronts the open portion of the housing IE it snugly receives the same.

The inner portion of the down draft tube I2 is provided with a collar having a pair of substantially semi-circular horizontal flanges 213 and 24 which cooperate to define a horizontal opening within the down draft tube and serve to retain the cap member 20 in place over the opening. The flanges 23 and 2d are secured to the down draft tube by means of bolts or other fastenings 25 passing through the down draft tube and depending flanges of the collar. The flanges 23 and 24 are offset vertically for a purpose to be described later.

Within the down draft tube |2 and at a point near its upper portion is located a damper 26 having a flat side 21 which corresponds to the shape of the opening defined by the flanges 23 and 24.

The damper 26 is mounted for relative rotation on a rotatable pintle rod 28 journalled in the collar provided with the flanges 23 and 24 and projects through the down draft tube l2 and through the opening 22 in the cap 20 into the cylinder Hi. In its closed position the damper 26 will rest upon the top of flange 23 on one side of the pintle rod 28 and will abut against the underside of the flange 24 on the opposite side of pintle 28. 24 serve as stops to engage the damper in the fully closed portion thereof.

One end of the pintle rod is extended through the draft tube [2 and cap 20 and projects into the cylinder or housing l6 which in turn is projected through the wall of the stove. The end of the rod projecting into the cylinder H is split for a short distance to receive the inner end of a volute thermostat member 29, and a cotter key 30 is inserted through the split portion to retain the thermostatic element in place. An arm 3| is secured to the damper in spaced parallel relation to the pintle 28 and extends through the arcuate slot 2| in the cap 20, as particularly shown in Figure 2. Slot 2| has its axis coincident with the axis of the pintle 28. The outer end 32 of the thermostatic element 29 is secured to the end of arm 3| which in turn is rigidly secured to the damper 26.

The other end of pintle 29 extends through the opposite sideof the draft tube I2 and is bent to form an ofiset end portion or crank 33 which extends through an arcuate graduated slot in a dial plate 34 supported in spaced relation to the draft tube by means of bolts or other fastenings 35. A knurled nut 33 is threaded on the end portion 33 of the pintle 28 and may be tightened to clamp against the dial plate 34.

The thermostatic carrying pintle 28 is angularly set at the desired point by means of the Consequently, the flanges 23 and nut 35 which looks the end 33 of pintle 23 in the graduated slot of the dial plate 34 at the desired point. This adjustment controls the temperature at which the thermostatic element will move the damper 26 as one end of the thermostatic element 29 is rigidly secured to the pintle 28 and the other end is secured to the damper 265 by means of the arm 3|.

As thus described, the present invention defines a thermostatic element 29 which is projected through the wall of the stove and is surrounded by a protective cylinder or housing l6 which is internally in communication with room air currents through the slot 2| in the cap 20. The cylinder |6 by means of the perforations 9 is also in communication with the combustion chamber of the stove. Accordingly the thermostatic element 29 operates upon a new principle, namely, the combined heat of the stove and the tempering and modifying action of the room air currents which permit the temperature of the room in which the stove is located some influence in governing the expansion and contraction of the thermostat and, consequently, the regulation of the fire.

The cylinder or housing i6 serves a threefold purpose. In the first place, it protects the thermostat 29 and its associated elements from injury in refueling the stove. Ordinarily stoves of this character are charged or refueled from the top by throwing in wood or other fuel and in so doing the thermostatic element 29 would be subject to injury unless protected by the housing is. Secondly, the cylinder l6 serves as a confined space in which a circulation of air is established from the outside atmosphere. Thirdly, it protects the thermostatic element 29 from the deteriorating effect of the flames of the fire in the stove.

The characteristics of the thermostatic element 29 are such that it is important to retain as much as possible its inherent elasticity whereby its tendency to re-coil when cold will not be destroyed. If the thermostat was continuously subject to the direct fire or flames contained within the stove, it would tend to lose its temper with the result that the springiness of the element would be destroyed and its intended function lost. The slot 2| in the cap 20, which is wholly above the damper when the damper is in the fully closed position, also serves to protect the thermostatic element from losing its intended functions. The air exteriorly of the stove passes into the draft tube l2 and from the draft tube .it is drawn into the cylinder it through the slot 2| and cools the thermostatic element which not only causes actuation of the thermostat by the room air current but in addition serves to protect the thermostat from the ravaging effects of the direct heat.

In operation with the damper in the vertically or fully open position shown in Figure 1, a fire is built in the combustion chamber of the stove.

As thus described, the draft tube i2 permits oxy gen to be conducted into the combustion chamber of the stove and the fire therein may burn briskly. As soon as the fire has reached a suitable intensity the thermostatic element 29 becomes heated from the flames of the fire and tends to uncoil and in so doing will finally position the damper 26 in a horizontal or fully closed position as shown in Figure 2. In this position, the arm 3| which travels in the arcuate slot 2| will be at the lower limit of such slot and the remaining part .of the slot is in communication with the outside atmosphere and with the housing I6. Air exteriorly of the stove is thus fed to the cylinder Hi, around the thermostatic element 29, and exits into the stove through the perforations H! as indicated by the arrows in Figure 3.

Thus as distinguished from the prior art, it is not necessary for the fire to subside considerably and cool the stove before the thermostatic element is actuated to open thedamper. The present arrangement permits the actuation of the damper in accordance with the temperature surrounding the stove which is lower than the lowest point to which the fire can fall before going out. Accordingly, due to the dual responsiveness of the thermostatic member a fairly consistent degree of heat may be had in the vicinity of the stove.

It will be understood that I have shown in the drawing, and described in the foregoing speciflcation, only one embodiment of which the invention is susceptible but that changes and modiiications may be made in the herein described specific embodiment without departing from the spirit of. the invention; providing only such changes falling within the scope of the following claims.

What is claimed is:

1. In a stove having means for conducting air to the combustion chamber thereof, a shaft journailed in the walls of said conducting means, a damper positioned in said conducting means and carried by said shaft, a thermostatic device carried by said shaft interiorly of said stove, a housing surrounding said thermostatic device and projecting exteriorly of the stove, a cap member within the air conducting means and adapted to snugly receive the projecting portion of the housing, said cap member having an opening lying wholly above the damper in its closed position in communication with the atmosphere to be heated by the stove and with the interior of the housing, and an operative connection between said thermostatic device and said damper.

2. The combination with a stove having an air admission opening and an air inlet conduit secured to said stove over said opening to communicate with the interior of the stove, of a shaft in said conduit, a damper carried by said shaft and mounted in said conduit, a volute thermostatic member secured at one end to said shaft within said stove, operative connecting means between said thermostatic member and said damper, a cup-shaped housing surrounding said thermostatic member and projecting exteriorly of the stove, said housing having perforations discharging into the stove, a cap member secured in said conduit and adapted to receive the projecting end of the housing, said cap member having an armate slot in communication with the atmosphere surrounding the stove and with the interior of the cup-shaped housing, said arrangement adapted to permit air to be drawn through said cap member into the housing and over the thermostatic member and discharged into the stove, and adjusting means carried by the other end of the projecting shaft.

3. The combination with a stove having an air admission opening and an air inlet conduit connected to said air admission opening, of a hous ing extending into the interior of the stove at one of its ends, a damper in said conduit, 8. thermostat disposed in the portion of thehousi'ng arranged within the stove, and means operatively connecting the thermostat and damper for varying the operative position of said damper, said housing also extending into the air inlet conduit adjacent said dampen there being an opening in the housing communicating with the interior of the conduit at a point above the damper in the closed position of the damper, said housing having an opening adjacent its other end communicating with the interior of the stove. U

4. The combination with a stove having man admission opening and an air inlet conduit nected to said air admission opening, of a housing extending into the interior of the stove at one of its ends, a damper in said conduit, 9. thenmostat disposed in the portion of the housing fifranged within the stove, and means operativly connecting the thermostat and damper for varying the operative position of said damper, said housing also extending into the said inlet conduit adjacent said damper, there being an opening in the housing communicating with the interior of the conduit at a point above the damper in the closed position of the damper, said housing having an opening adjacent its other end communicating with the interior of the stove, said thermostat being disposed between the openings in the housing to be in the path of air passing from the conduit through the housing to the stove.

5. The combination with a stove having an air admission opening and an air inlet conduit connected to said opening, of a housing disposed within the interior of the stove and extending into the interior of the conduit, a shaft extending through said conduit and into that portion'of the housing in the stove, a damper carried by said shaft in the conduit, said housing having openings at each end thereof, a thermostat carried by the shaft extending into the housing within stove, and means operatively connecting the thermostat and damper for varying the position of the damper.

6. The combination with a stove having an air admission opening and an air inlet conduit connected to said opening, of a housing disposed within the interior of the stove and extending into the interior of the conduit, a shaft extending through said conduit and into that portion'o! the housing in the stove, a damper carried by said shaft in the conduit, said housing'having openings at each end thereof, a thermostat carried by J the shaft extending into the housing within stove, and means operativoly connecting the thermostat and damper for varying the position of the damper, one of said openings in the housing communicating with the interior of the conduit at a point above the damper in the closed position and the other of said openings communicating with the interior of the stove at a point below the thermostat.

'7. In a stove having means for conducting air to the combustion chamber thereof, a shaft Journalled the walls of the conducting means, a damper positioned in said conducting means and carried by said shaft, a cup shaped housing disposed within the interior of the stove with its open end projecting into the conducting means, a thermostat disposed in said housing within the stove, a cap member adapted to close the open end of the housing, and means operatively connecting the thermostat and damper for varying the operative position of said damper.

JULIUS C. BARNES. 

